Telegraph signaling system



1,6 1,174 M 1927' s. o. WILBURN 3 TELEGRAPH SIGNALING SYSTEM Filed Dec. 7. 1923 (NVEN TOR 61D. Wzwalrm Patented June 7, 1927.

UNITED STATES" PATENT OFFICE.

SIDNEY n-WILE RN, 0E ENeLEwoon N w JERSEY, ASSIGN'OR T0 AMERICAN TELE- IIeIoNE AND TELEGRAPH GOMPANY,- A CORPORATION OF NEW YORK.

TELEGRAPH SIGNALING SYSTEM.

Application fiIed December 7, 1923. Serial No. 679,193.

This invention relates to telegraph signaling systems and particularly to an arrangement for facilitating the calling of the attendant at a repeater station by the operator of a subscribers line connected with the a said repeater station.

In the operation of a telegraph system furnishing service to a plurality of subscribers it is desirable that the operator of any subsignals are unsatisfactory. In a system in which the subscribers loop circuit-s are fullmetallic circuits it is customary to connect the metallic circuit with duplicate windlngs of a neutral relay, WhlCll are 1n turn connected with a source of current supply. In.

such an arrangement the currents in both windings are substantially equal and, theirmagnetic effects are opposed, so that the armature of such relay is normally unaffected.

F If, however, one side of the subscribersloop is intentionally grounded at the subscribers station by the operation of a push button or equivalent-device, the relay will be unbalanced, and, when it operates, it closes a circuit through a signaling device, either visual or audible or both, the object of which is to attract theattention 0f the attendant at the repeater station. VVh-en a subscribers circuit is connected with the repeater station by a single wire grounded circuit, as distinguished from the full metallic circuit referred to above, it will, or course, be apparent that the use of a balanced relay is not practicable for the operation of a calling-in signal.

In such cases if the single wire grounded. circuit be comparatively short, a signal to the repeater station may be effected by the subscriber by means of a single winding relay included in the subscribers circuit at the repeater station. This relay would have to be non-operative on the normal current in the subscribers circuit and operative, on an increase of current obtained by the shunting out of a resistance'at the subscribers station when he wishes to signal. Thus the operation of the calling-in relay at the re peater station is marginal and in the case of a long subscribers circuit operated over a wire to ground, the resistance of the circuit may be such that sufficient margin of current is not obtainable. In addition, if such a single wire grounded circuit of considerable length be operated over open wire lines, leakage will further tend to makethis method inefficient.

It is accordingly the object of this invention to provide a calling-in signal for long subscribers'circuits or lines operated by'the single Morse method. This invention will be clearly understood from the following description when read in connection with the attached drawing, of which Figure 1 shows a form of embodiment of the invention in which the polar relay controlling the system is connected in shunt toground and Fig. 2 shows an embodiment of the invention in which the said polar relay is connected in series with the line. I I

In Fig. 1, L represents a line extending from the repeater station A to a distant ofiice B. L represents a subscribers line circuit extending from the repeater station I A to the sub'station'C, terminating there upon the movable arm of the switch 1. When this arm is moved'to its upper contact the line L will be connected through the key 2, the line relay 3 and the battery 4 to ground. In practice, the relay 3, would, of course, control a sounder or other similar device but it is not deemed necessary to show this additional equipment to describe the in vention. When the arm 1 is moved to its lower contact the line L willbe connected through the 16 cyclegenerator to ground. The invention is not limited to the particular frequency mentioned or to any particular form of apparatus. At the repeater station A the'line L is connected through the winding 6 of the repeater with the armature 11, controlled by winding 7 of the same repeater. 7 Sources of potentials and9 are connected with'the contact and with the wind- Con.-

ing of relay 7 in the manner shown.

nected with the line L in shunt to ground is 16 is grounded and the contact thereof is connected through the ],'0S1Stt:.110 21 and the source of potential 22 to ground. Connected in series with the said resistance and source "of potential is the winding of relay 23,

connected therewith the'switch 1 is maintained closed in its upper position. Upon the closing 01 key 2 a signaling impulse will .be transmitted over a circuit comprising battery. 4, relay 3, key 2, upper contact of switch 1, line L winding of relay '6, contact'ot armature 11 and battery Sto ground, thereby energizing relay 6 so as to attract its arma ture 10. Upon the closing ot the contact of relay 6 a circuit will be established from grounded battery 9, winding of relay 7, contact of armature 10 of relay 6 and line L to and through the receiving-apparatus located atfthe distant otlice B. The polar relay 12 is adjusted so as not to respond ellicient-ly to the impulses 0t Morse signaling current transmitted over. the line L Any operati'on ot relay 12 due to Morse signals will be prevented from causing a talse 'call ing-in signal by the use of slow-acting relays in the circuit controlled by the relay 12. A signaling impulse transmitted from the distant otiice B over the line L, will flow through the contact of relay 6 and the winding oi relay 7 and upon attracting its urinature 11. will send an impulse from battery 8, over the line L to the substation C. The repeater, made up of the relays 6 and '7 and the associated batteries, is shown in its siniplest form without the usual holding coils ordinarily found in repeaters of this type because the repeater per se does not form a partof this invention.

I It the operator at the substation CeXperiences any diiiiculty in'the reception of signals or for any other reason desires to attract the attention of the attendant at repeater station A, he moves the arm of sw tch 1 to its downward position, thereby closing, a

circuit which includes the 16, cycle generator 5, lower contact of switch 1, the 1111611 polar relay 12, res1sta'nce'26 and condenser ,20 to ground. The polar relay 12 will op-' e'rate and its armature will move between its contacts 14 and 15 1n accordance with the cyclic changes of the current flowing over the line 12,. When the armature ot the polar relay 12 touches its contact 141, current will flow from the source 13 through the contact 14 of relay 12, then in two parallel paths to ground, one through condenser 17, relay winding 16 and resistance 18 to ground and the other through resistance 19 to ground. Thus, relay 16 is energized and condenser 17 is charged. hen the armature of relay 12 touches the contact 15, current will flow from the source 13 through contact 15 of relay 12 and then in two parallel paths to ground, one

through relay winding 16, condenser 17 and resistance 19 to ground, and the other through resistance 18 to ground. Thus, re-

lay 16 is again energized and condenzier 17 again charged. It will be noted that the charge received by condenserll', when the armature of relay 12 wason its contact 1 1, is in such a direction as to aid the current flow through relay winding 16 when the arinatureot relay 12 touches the contact 15. The converse is also true. In addition, relay 16 is a slow release relay, providing tor continued operation of the signal when once started. It will be seen that relay 23 is normally energized and its armature held up-by current flowing from the source 22 through resistance 21 and the winding of relay 23. Upon the energization of relay 16its armature touches its upper contact which establishes a shunt path around the source22 and the resistance 21-, which effects the release of relay 23 and thereby allows its armature to drop. This closes the circuit of the signaling device 2 1 andoperates said device. Relay 23 is a slow release relay to prevent false signaling which might be caused by the operation of relay 12 by Morse signals in the line L The circuit of Fig. 2, in which the same reference symbols have been used to indicate parts similar to those shown in Fig. 1, lit ters structurally from Fig. 1 in'that the polar relay 12 is connected in series with the line L instead of in shunt therewith, as shown in Fig". 1. in the transmission and reception of signals the apparatus at the re peater station A and at the substation C operates in the same manner in Fig. 2 as in Fig. 1 and needs no further explanation. lVheri the operator at substation Cot Fig. 2 desires to attract the attention of the repester attendant he closes the switch 1 in its downward position, thereby transmitting 16 cycle current from the source 5 over the line L through the windings of polar relay 12 and the windin'gof relay 6 or the repeater, thence through the contact 11 of relay 7 and through battery 8 to ground. This current will eitl 'ect the cyclic movement of the armature or the polar relay 12. hen the armature of the polar relay 12 touches its contact 1 1, current will 'flow from the source 13 through the contact 1 1 of relay 12, then in two parallel paths to ground,

' combination with a line, of a sub-station one through condenser 17, relay winding lfi lay 16 is energized and Condenser 17 is -cliarged. When the armaturetotrelay 12 touches the contact 15, current will' flow "from the source 13 throughIcontact 15 of i'elay 12 and then in two parallel paths 'to ground, one through relay winding 16, condenser 17 and resistance 19 to ground, and the other through resistance 18 to ground. Thus, relay 16 is again energized and condenser 17 gain charged. It willbe noted that the c arge received by condenser 17, when the armature of relay 12 was on its contact 14:, is in such a direction as to aid the current flow through relay winding 16 when the armature of relay 12 touches the contact 15. The converse is also true. In addition, relay 16 is a slow r'elease relay, providing for continued operation of the signal when once started. When relay 16 is energized the source 22 and the resistance 21 are shunted by a path through the contact of relay 16, whereby relay 23 is released. The releasing of this latter relay closes a circuit containing the signaling device 24, thereby operating the said device. Relay 23 is a slow release relay to prevent false signaling which might be caused by the operation of relay 12 by Morse signals in the line L I While the polar relay 12 may be operated either bridged to ground, as in Fig. 1, or in series with the line, as in Fig. 2, there are certain practical advantages in'connecting the polar relay inshunt to ground. With that arrangement the subscriber willbe able to signal the repeater attendant even though the wire may be open at the repeater station a or somewhere upon the main line L 'The arrangement of the polar relay, which would produce the least effect upon the Morse operation of the circuit, depends upon the value of the resistance and the admittance oi the condenser in series with the relay.

It the operating margin of the polar relay is such as to permit the use of a resistance of high value and a condenser of sufficiently high impedance the shunt-to-gro'und arrangement would probably be preferable.

While this invention has been disclosed as embodied in a particular form and arrangement of parts'it is to be understood that it is not so limited but is capable of embodiment in other and diflerent forms without departing from the spirit and scope of the appended claims.

\Vhat is claimed is:

1. In a telegraph signaling system, the

and a repeater station, said sub-station having connected therewith a source of alternating current, and means for connecting the said source to the said line, and the said repeater stat-ion havinga polarized relay responsive to the said alternating, current and arranged to, control a signaling device. 2. In a. telegraph signaling system, the

coi'nliination with a line,'ot a sub-station and a repeater station, the said sub-station comprising a telegraplibranch, a-signaling branch having a source of alternating current connected therewith, and means to connect either of said branches'to said line,

and the said repeater station having a polarized relay responsive to the said alternating current and arranged to control a signaling device.

3..In a telegraph signaling system, the

combination with a line, of a sub-station and a repeater station. said sub-station having connected therewith a source of alternating current, and'means for connecting the said source to the said 11116, and the said repeater station having a signaling branch comprising a polarized relay connected be tween thesaid line and ground having means associated therewith to energize and deenergize a second relay, a third relay controlled by the said second relay, and signaling means operated by the said third relay.

4. In a single line Morse repeater, the combination with a plurality of line circuits one of which has a source of alternating current connected therewith, of repeating relays and sources of potential arranges to amplify the signals received from one line circuit and to impress them upon the other line circuit, anda signaling circuit connected with one of said line circuits comprising a polarized relay responsive to said alternating current, and means controlled by the said polarized relay to operate a signaling device.

5. In a single line Morse repeater, the combination with a plurality of line circuits one of which has a source of alternating current connected therewith, of repeating relays and sources of potential arranged to amplify the signals received from one line circuitand to impress-them upon the other line circuit. a signaling circuit connected to ground from one of said line circuits having a polarized relay connected therewith, and

means controlled by the said polarized relay to operate a signaling device.

6. In a single line Mort-e telegraph sy tom, the combination witha repeater station, of a substation, a line connecting the said stations, and signaling means located at said repeater station responsive to alter-' nating current'applied to said line at said sub-station.

a single line Morse repeater, a Morse sub-I scriber' station having means to apply either Morse signals or alternating current'to the said line, the said Morse repeater having means responsive to the sniclalternating current to control the operation of a signaling device.

8:111 a telegraph signaling system the combination with a line of a substation having a source of telegraph current, a

source of signaling; current and means to connect either source to said hue, and a repeater station. having a signal device connected therewlth',.responsrve to sand signal- 111g current and not to the telegraph current. 7- .e 

